Method and apparatus for delivering combined electrical and drug therapies

ABSTRACT

A cardiac rhythm management (CRM) system includes an implantable medical device that delivers combined electrical and drug therapies. The implantable medical device includes a drug reservoir that is refillable after implantation. In one embodiment, the implantable medical device includes an implantable housing encapsulating a pulse generator circuit and a drug delivery device. In another embodiment, the implantable medical device includes an implantable pulse generator and an implantable drug delivery device fastened to each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to co-pending, commonly assigned U.S. patentapplication Ser. No. 10/862,716, filed on Jun. 7, 2004, U.S. patentapplication Ser. No. 10/742,574, filed on Dec. 19, 2003, U.S. patentapplication Ser. No. 10/645,823, filed on Aug. 21, 2003, U.S. patentapplication Ser. No. 10/435,487, filed on May 9, 2003, U.S. patentapplication Ser. No. 10/293,907, filed on Nov. 12, 2002, U.S. patentapplication Ser. No. 10/184,019, filed on Jun. 28, 2002, U.S. patentapplication Ser. No. 10/172,825, filed on Jun. 14, 2002, and U.S. patentapplication Ser. No. 10/079,056, filed on Feb. 19, 2002, which arehereby incorporated by reference in their entirety.

TECHNICAL FIELD

This document generally relates to cardiac rhythm management (CRM)systems and particularly, but not by way of limitation, to such a systemusing implantable medical devices to deliver combined electrical anddrug therapies.

BACKGROUND

The heart is the center of a person's circulatory system. It includes anelectro-mechanical system performing two major pumping functions. Theleft portions of the heart draw oxygenated blood from the lungs and pumpit to the organs of the body to provide the organs with their metabolicneeds for oxygen. The right portions of the heart draw deoxygenatedblood from the organs and pump it into the lungs where the blood getsoxygenated. The pumping functions are accomplished by contractions ofthe myocardium (heart muscles). In a normal heart, the sinoatrial node,the heart's natural pacemaker, generates electrical impulses, known asaction potentials, that propagate through an electrical conductionsystem to various regions of the heart to excite myocardial tissues inthese regions. Coordinated delays in the propagations of the actionpotentials in a normal electrical conduction system cause the variousregions of the heart to contract in synchrony such that the pumpingfunctions are performed efficiently.

A blocked or otherwise damaged electrical conduction system causes themyocardium to contract at a rhythm that is too slow, too fast, and/orirregular. Such an abnormal rhythm is generally known as arrhythmia.Arrhythmia reduces the heart's pumping efficiency and hence, diminishesthe blood flow to the body. A deteriorated myocardium has decreasedcontractility, also resulting in diminished blood flow. A heart failurepatient usually suffers from both a damaged electrical conduction systemand a deteriorated myocardium. The diminished blood flow results ininsufficient blood supply to various body organs, preventing theseorgans to function properly and causing various symptoms.

Various electrical therapies are available to treat cardiac disorderssuch as various types of arrhythmias and heart failure. These electricaltherapies, including pacing and defibrillation therapies, are deliveredto various locations of the heart. Various drug therapies are alsoavailable to treat cardiac disorders. Some drugs are most efficient oreffective when directly applied to the heart, such as to a cardiacregion where a disorder originates.

When properly combined, electrical and drug therapies may benefit apatient to an extent beyond what is achievable by either drug therapy orelectrical therapy alone. In many circumstances, the electrical and drugtherapies are most effective when delivered to specific target regions.Thus, there is a need for a system to perform localized delivery ofcombined electrical and drug therapies.

SUMMARY

A CRM system includes an implantable medical device that deliverscombined electrical and drug therapies. The implantable medical deviceincludes a drug reservoir that is refillable after implantation.

In one embodiment, a CRM system includes an implantable medical devicethat includes a pulse output circuit, a drug delivery device, an implantcontroller, and an implantable housing. The pulse output circuitdelivers electrical pulses to a heart. The drug delivery device includesa drug reservoir adapted to contain a drug and a reservoir filling port.The implant controller controls the delivery of the electrical pulsesand the drug. The implantable housing contains the pulse output circuit,the drug delivery device, and the implant controller. The reservoirfilling port is constructed on the implantable housing and includes aself-resealable portion that allows filling of the drug reservoir usinga hollow needle.

In another embodiment, a CRM system includes an implantable pulsegenerator and an implantable drug delivery device fastened to theimplantable pulse generator. The implantable pulse generator, whichdelivers electrical pulses to a heart, includes a pulse generatorcircuit and an implantable housing that encapsulates the pulse generatorcircuit. The implantable drug delivery device, which delivers a drug,includes a drug reservoir, an implantable housing, and a reservoirfilling port. The drug reservoir contains the drug. The implantablehousing of the implantable drug delivery device encapsulates portions ofa structure for drug delivery including the drug reservoir. Thereservoir filling port is constructed on the implantable housing of theimplantable drug delivery device. The reservoir filling port includes aself-resealable portion that allows filling of the drug reservoir usinga hollow needle. The two implantable housings are fastened to eachother.

In one embodiment, a medical device assembly is provided for use with animplantable CRM device. The medical device assembly includes animplantable drug delivery device and means for fastening the implantabledrug delivering device to the implantable CRM device. The implantabledrug delivery device includes a drug reservoir, an implantable housing,and a reservoir filling port. The drug reservoir contains the drug. Theimplantable housing, which contains portions of a structure of theimplantable drug delivery device including the drug reservoir, isconfigured to be attached to the implantable CRM device. The reservoirfilling port is constructed on the implantable housing and includes aself-resealable portion that allows filling of the drug reservoir usinga hollow needle.

In one embodiment, a method for making an implantable CRM system isprovided. A pulse generator circuit is provided to deliver electricalpulses to one or more electrodes. A drug delivery device including adrug reservoir is also provided.

The pulse generator circuit and the drug delivery device areencapsulated using an implantable housing. A self-resealable reservoirfilling port is incorporated onto the implantable housing to allowfilling of the drug reservoir using a hollow needle.

In one embodiment, a method for making an implantable medical device isprovided. An implantable pulse generator is provided. The implantablepulse generator includes an implantable pulse generator housing. Animplantable drug delivery device is also provided. The implantable drugdelivery device includes a drug reservoir, an implantable drug deliverydevice housing, and a self-resealable reservoir filling port.

The self-resealable reservoir filling port is constructed on theimplantable drug delivery device housing to allow filling of the drugreservoir using a hollow needle. The implantable drug delivery devicehousing is fastened to the implantable pulse generator housing.

This Summary is an overview of some of the teachings of the presentapplication and not intended to be an exclusive or exhaustive treatmentof the present subject matter. Further details about the present subjectmatter are found in the detailed description and appended claims. Otheraspects of the invention will be apparent to persons skilled in the artupon reading and understanding the following detailed description andviewing the drawings that form a part thereof, each of which are not tobe taken in a limiting sense. The scope of the present invention isdefined by the appended claims and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe similar components throughout the several views. The drawingsillustrate generally, by way of example, but not by way of limitation,various embodiments discussed in the present document.

FIG. 1 is an illustration of an embodiment of a CRM system including animplantable system and an external system and portions of an environmentin which the CRM system is used.

FIG. 2 is an illustration of an embodiment of the implantable system.

FIG. 3 is an illustration of another embodiment of the implantablesystem.

FIG. 4 is an illustration of another embodiment of the implantablesystem.

FIG. 5 is an illustration of another embodiment of the implantablesystem.

FIG. 6 is a block diagram illustrating one embodiment of the circuit ofportions of the CRM system.

FIG. 7 is a block diagram illustrating another embodiment of the circuitof portions of the CRM system.

FIG. 8 is a flow chart illustrating one embodiment of a method formaking a CRM system delivering combined electrical and drug therapies.

FIG. 9 is a flow chart illustrating one embodiment of another method formaking a CRM system delivering combined electrical and drug therapies.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that the embodiments may be combined, or that otherembodiments may be utilized and that structural, logical and electricalchanges may be made without departing from the spirit and scope of thepresent invention. The following detailed description provides examples,and the scope of the present invention is defined by the appended claimsand their equivalents.

It should be noted that references to “an”, “one”, or “various”embodiments in this disclosure are not necessarily to the sameembodiment, and such references contemplate more than one embodiment.

This document discusses, among other things, a CRM system using one ormore implantable medical devices to deliver combined electrical and drugtherapies to the heart. In this document, a “drug” includes one or moreagents intended for use in the diagnosis, cure, mitigation, treatment,or prevention of one or more diseases. The one or more agents may bechemical, biochemical, and/or biological in nature. Such agents include,but are not limited to, agents treating an arrhythmia, agents treatingheart failure, agents treating diastolic dysfunction, agents providingischemia protection, agents reducing fibrosis, angiogenic agents, agentssupporting a cell therapy, agents recruiting cells for cell therapy, andagents promoting tissue regeneration and development.

FIG. 1 is an illustration of an embodiment of a CRM system 100 andportions of an environment in which CRM system 100 is used. System 100includes an implantable system 115 and an external system 145.Implantable system 115 includes an implantable medical device 110 and alead system 108. In one embodiment, external system 145 includes anexternal device 150, a network 160, and a remote device 170. In anotherembodiment, external system 145 includes a medical device programmer. Asshown in FIG. 1, implantable medical device 110 is implanted in a body102 to deliver a combined electrical and drug therapy to a heart 105. Adrug is stored in implantable medical device 110, which includes a drugfilling port 114 to allow filling of the drug after implantation in body102. In one embodiment, drug filling port 114 includes a self-resealablediaphragm constructed on the housing of implantable medical device 114to allow filling of the drug using a hollow needle. Lead system 108,which provides connections between implantable medical device 110 andheart 105, includes one or more pacing and/or defibrillation leads, drugdelivery leads, and/or drug delivery pacing and/or defibrillation leads.A telemetry link 140 provides for bidirectional communication betweenimplantable medical device 110 and external device 150. Network 160provides for bidirectional communication between external device 150 andremote device 170.

The delivery of the electrical and drug therapies is controlled by oneor more of implantable medical device 110, external device 150, andremote device 170. In one embodiment, implantable medical device 110controls the delivery of the electrical and drug therapies based on adetected signal or condition. In one embodiment, external device 150and/or remote device 170 control the delivery of the electrical and drugtherapies upon receiving an external command from a physician or othercaregiver. In further embodiments, external device 150 and/or remotedevice 170 are capable of automated controlling the delivery of theelectrical and drug therapies by processing and analyzing signals and/orconditions detected by implantable medical device 110.

FIG. 2 is an illustration of an implantable system 215 being oneembodiment of implantable system 115. Implantable system 215 includes animplantable medical device 210, which is an embodiment of implantablemedical device 110, and a lead 208, which is a lead of lead system 108.

Implantable medical device 215 includes at least a pulse generatorportion to deliver an electrical therapy and a drug delivery portion todeliver a drug therapy. The pulse generator portion includes circuitryfor delivering electrical therapies including, but not being limited to,pacing therapy, cardiac resynchronization therapy (CRT), cardiacremodeling control therapy (RCT), and cardioversion/defibrillationtherapy. The drug delivery portion includes a drug pump to deliver adrug and a drug reservoir to contain the drug. Implantable medicaldevice 210 includes a can 211 and a header 212 attached to can 211. Can211 is a hermetically sealed implantable housing encapsulating portionsof the circuitry and other components of the pulse generator and drugdelivery portions. Header 212 includes a connector providing forconnection between lead 208 and implantable medical device 210.Implantable medical device 210 includes a reservoir filling port 214 toallow filling of the drug reservoir through a hollow needle. Reservoirfiling port 214, which is an embodiment of drug filing port 114, isconstructed on can 211 and includes a self-resealable diaphragm that ispunctured by the hollow needle for access to the drug reservoir andself-resealed when the hollow needle is pulled out.

In one embodiment, as illustrated in FIG. 2, lead 208 is a drug deliverypacing lead, i.e., a drug delivery lead with at least one pacingelectrode. Lead 208 includes a proximal end 209 and a distal end 207.Proximal end 209 is connected to implantable medical device 210 atheader 212. Lead 208 includes a drug delivery port 218. In oneembodiment, as illustrated in FIG. 2, drug delivery port 218 is neardistal end 207. In another embodiment, drug delivery port 218 is inanother location along lead 208, away from distal end 207. A lumen 206extends within lead 208 from proximal end 209 to drug delivery port 218.Lumen 206 allows passage of the drug from the drug delivery portion ofimplantable medical device 210 to drug delivery port 218. In oneembodiment, drug delivery port 218 is an opening through which the drugfollows out of lumen 206. In another embodiment, drug delivery port 218is made of a porous material such as a porous polymer for controllingthe speed of drug release. In one embodiment, as illustrated in FIG. 2,lead 208 is a unipolar pacing lead including a tip electrode 216 atdistal end 207. Pacing pulses are delivered to heart 105 through tipelectrode 216 and can 211, which is used as another electrode. Inaddition to passing the drug, lumen 206 is also configured toaccommodate a portion of a guidewire for implanting lead 208. In oneembodiment, lead 208 is an epicardial lead with distal end 207configured for epicardial placement. In another embodiment, lead 208 isan endocardial lead with distal end 207 configured for endocardialplacement.

FIG. 3 is an illustration of an implantable system 315 being anotherembodiment of implantable system 115. Implantable system 315 includesimplantable medical device 210 and a drug delivery pacing lead 308. Lead308 is a lead of lead system 108 and includes a proximal end 309 and adistal end 307. Proximal end 308 is connected to implantable medicaldevice 210 at header 212. In additional to the features of lead 208,lead 308 includes multiple drug delivery ports 318A-E. A lumen 306extends within lead 308 from proximal end 309 to each of drug deliveryports 318A-E. Lumen 306 allows passage of the drug from the drugdelivery portion of implantable medical device 210 to the each of drugdelivery ports 318A-E. The number and distribution of the drug deliveryports as illustrated in FIG. 3 are for illustrative purpose only. Theactual number and distribution of the drug delivery ports are determinedbased on the therapeutic needs, including the need and circumstances ofeach individual patient. In one embodiment, drug delivery ports 318A-Eincludes one or more drug delivery ports each being an opening throughwhich the drug follows out of lumen 306. In another embodiment, drugdelivery ports 318A-E includes one or more drug delivery ports each madeof a porous material such as a porous polymer for controlling the speedof drug release.

FIG. 4 is an illustration of an implantable system 415 being anotherembodiment of implantable system 115. Implantable system 415 includes animplantable medical device 410 being another embodiment of implantablemedical device 110. Implantable medical device 410 includes animplantable pulse generator 410A and an implantable drug delivery device410B, which are fastened to each other to form a single implantabledevice. Examples of implantable pulse generator 410A include, but arenot limited to, a pacemaker, a CRT device, an RCT device, acardioverter/defibrillator, and a pacemaker-cardioverter/defibrillator.Leads 408A and 408B are leads of lead system 108.

Implantable pulse generator 410A includes a can 411A and a header 412Aattached to can 411A. Can 411A is a hermetically sealed implantablehousing encapsulating portions of the circuitry and other components ofimplantable pulse generator 410A. Header 412A includes a connectorproviding for connection between a pacing lead 408A and implantablepulse generator 410A. Implantable drug delivery device 410B includes acan 411B and a header 412B attached to can 411B. Can 411B is anotherhermetically sealed implantable housing encapsulating portions of thecircuitry and other components of implantable drug delivery device 410B.Header 412B includes a connector providing for connection between drugdelivery lead 408B and implantable drug delivery device 410B.Implantable drug delivery device 410B includes a drug reservoir andreservoir filling port 214 to allow filling of the drug reservoirthrough a hollow needle. Reservoir filing port 214 is constructed on can411B and includes a self-resealable portion that is punctured by thehollow needle and self-resealed when the hollow needle is pulled outduring a reservoir filling.

In one embodiment, implantable pulse generator 410A and implantable drugdelivery device 410B are fastened to each other by gluing can 411A andcan 411B together with a biocompatible adhesive in the manner shown inFIG. 4. In a further embodiment, header 412A and header 412B are alsoglued together. In alternative embodiments, implantable pulse generator410A and implantable drug delivery device 410B are fastened to eachother by welding, bracing, soldering, or any other means for makingimplantable pulse generator 410A and implantable drug delivery device410B permanently attached to each other. In one embodiment, implantablepulse generator 410A and implantable drug delivery device 410B haveapproximately identical major contours. They are aligned and thenfastened to form implantable medical device 410.

In one embodiment, implantable drug delivery device 410B is provided foradding drug delivery function to an implantable CRM device that is anexisting product or a product developed independently from anyimplantable drug delivery device. In one specific embodiment, a unit ofimplantable drug delivery device 410B and means for fastening it to theimplantable CRM device are provided as an assembly to the physician orother caregiver. Example of the means for fastening includes, but is notlimited to, a medical grade adhesive for gluing the unit of implantabledrug delivery device 410B to the implantable CRM device. In a furtherembodiment, the assembly also includes one or more drug delivery leadsrequired for adding the drug delivery function.

In one embodiment, as illustrated in FIG. 4, lead 408A is a bipolarpacing lead that includes a proximal end 409A and a distal end 407A.Proximal end 409A is connected to implantable pulse generator 410A. Inaddition to tip electrode 216, lead 408A includes a ring electrode 417near distal end 216. Pacing pulses are delivered through a pair ofelectrodes being one of electrodes 216 and 417, tip electrode 216 andcan 411A, and ring electrode 417 and can 411A. In one embodiment, lead408A is an epicardial lead with distal end 407A configured forepicardial placement. In another embodiment, lead 408A is an endocardiallead with distal end 407A configured for endocardial placement.

Lead 408B is a drug delivery lead that includes a proximal end 409B anda distal end 407B. Proximal end 409B is connected to implantable drugdelivery device 410B. Lead 408B includes a drug delivery port 218. Inone embodiment, as illustrated in FIG. 4, drug delivery port 218 is neardistal end 407B. In another embodiment, drug delivery port 218 is inanother location along lead 408B, away from distal end 407B. A lumen 406extends within lead 408B from proximal end 409B to drug delivery port218. Lumen 406 allows passage of the drug from the drug delivery portionof implantable drug delivery device 410B to drug delivery port 218. Inone embodiment, lead 408B is an epicardial lead with distal end 407Bconfigured for epicardial placement. In another embodiment, lead 408B isan endocardial lead with distal end 407B configured for endocardialplacement.

FIG. 5 is an illustration of an implantable system 515 being anotherembodiment of implantable system 115. Implantable system 515 includesimplantable medical device 410 and a drug delivery pacing lead 508 beinga lead of lead system 108. Lead 508 is a branched drug delivery pacinglead that includes proximal ends 509A and 509B and a distal end 507.Proximal end 509A is connected to implantable pulse generator 410A.Proximal end 409B is connected to implantable drug delivery device 410B.A lumen 506 extends within lead 408 from proximal end 509B to drugdelivery port 218. In one embodiment, as illustrated in FIG. 5, drugdelivery port 218 is near distal end 507. In another embodiment, drugdelivery port 218 is in another location along lead 508, away fromdistal end 507. Lumen 506 allows passage of the drug from implantabledrug delivery device 410B to drug delivery port 218. In one embodiment,as illustrated in FIG. 5, lead 508 is a bipolar pacing lead includingtip electrode 216 at distal end 507 and ring electrode 417 near distalend 507. Pacing pulses are delivered through a pair of electrodesincluding one of electrodes 216 and 417, tip electrode 216 and can 411A,and ring electrode 417 and can 411A. In addition to passing the drug,lumen 506 is also configured to accommodate a portion of a guidewire forimplanting lead 508. In one embodiment, lead 508 is an epicardial leadwith distal end 507 configured for epicardial placement. In anotherembodiment, lead 508 is an endocardial lead with distal end 507configured for endocardial placement.

The number and types of leads connected to implantable medical device110, including its embodiments such as implantable medical devices 210and 410, depend on the patient's therapeutic needs and the intended useof the implantable system. In various embodiments, implantable medicaldevices 210 and 410 may each include additional connectors toaccommodate more lead than those illustrated in FIGS. 2-5. The leads andimplantable devices illustrated in FIGS. 2-5 may be combined differentlywhen appropriate to form additional embodiments of implantable system115. The features on each lead as illustrated in FIGS. 2-5 may becombined to form additional embodiments of leads in lead system 108. Forexample, a ring electrode may be incorporated near distal end 207 oflead 208 to form a drug delivery bipolar pacing lead, and drug deliveryports 318A-E may be incorporated into lead 408B to form a drug deliverylead with multiple drug delivery ports. In embodiments in whichimplantable medical device 110 includes a cardioverter/defibrillatorcircuit, one or more defibrillation electrodes are incorporated into oneor more leads of lead system 108. In general, lead system 108 includesone or more of (i) drug delivery lead (lead with one or more drugdelivery ports), (ii) pacing lead (lead with one or more pacingelectrodes), (iii) defibrillation lead (lead with one or moredefibrillation electrodes), (iv) pacing/defibrillation lead (lead withone or more pacing electrodes and one or more defibrillationelectrodes), (v) drug delivery pacing lead (lead with one or more pacingelectrodes and one or more drug delivery ports), (vi) drug deliverydefibrillation lead (lead with one or more defibrillation electrodes andone or more drug delivery ports), and (vii) drug deliverypacing/defibrillation lead (lead with one or more pacing electrodes, oneor more defibrillation electrodes, and one or more drug delivery ports).The pacing and defibrillation electrodes are also used as electrodes forelectrogram sensing.

FIG. 6 is a block diagram illustrating one embodiment of the circuit ofportions of a CRM system 600. CRM system 600 is an embodiment of CRMsystem 100 and includes an implantable system and an external system.The implantable system includes implantable medical device 210 and leadsystem 108. The external system includes external device 150, network160, and remote device 170.

Implantable medical device 210 includes a sensor circuit 621, a pulseoutput circuit 622, an implant controller 624, a drug delivery device630, and an implant telemetry module 642. Implant telemetry module 642provides for a telemetry interface allowing implantable medical device210 to communicate with external device 150 via telemetry link 140.

Sensor circuit 621 senses one or more signals each indicative of a needto deliver at least one of the electrical and drug therapies. In oneembodiment, sensor circuit 621 includes an electrogram sensing amplifiercircuit to sense one or more electrograms. In a further embodiment,sensor circuit 621 includes one or more implantable sensors to senseadditional physiological signals. In one embodiment, the one or moreimplantable sensors include at least one sensor housed in can 211 ofimplantable medical device 210. In another embodiment, the one or moreimplantable sensors include at least one sensor incorporated into a leadof lead system 108.

Pulse output circuit 622 delivers electrical pulses to the heart throughelectrodes of lead system 108. Pulse output circuit 622 includes one ormore of a pacing circuit to deliver pacing pulses and acardioversion/defibrillation circuit to delivercardioversion/defibrillation shocks.

Implant controller 624 controls the operation of implantable medicaldevice 210. Implant controller 624 includes a sensor processing circuit625, a therapy controller 626, and a command receiver 627. Sensorprocessing circuit 625 processes the one or more signals sensed bysensor circuit 621 to produce diagnostic and/or therapeutic controlsignals. Command receiver 627 receives the external command entered bythe physician or other caregiver and sent from the external systemthrough implant telemetry module 642 and telemetry link 140. Therapycontroller 626 controls the delivery of the electrical and drugtherapies based on the therapeutic control signals and the externalcommand.

Therapy controller 626 includes an electrical therapy controller and adrug therapy controller. The electrical therapy controller includes apacing algorithm execution circuit to control the delivery of pacingpulses by executing a pacing algorithm. In one embodiment, the pacingalgorithm execution circuit executes a pacing algorithm designed toenhance one or more effects of the drug therapy. In a specificembodiment, the pacing algorithm execution circuit includes a CRT pacingalgorithm execution circuit to execute a CRT pacing algorithm. The CRTprovides for an approximately optimal hemodynamic performance. In oneembodiment, a CRT pacing algorithm is executed with one or more pacingparameters approximately optimized to maximize a measure of hemodynamicperformance. In another specific embodiment, the pacing algorithmexecution circuit includes an RCT pacing algorithm execution circuit toexecute an RCT pacing algorithm. The RCT alters the cardiac remodelingprocess, for example, by redistributing the workload and stress on theventricular walls. In a further specific embodiment, the pacingalgorithm execution module executes a dynamic pacing algorithm thatdynamically adjusts pacing parameters, such as alternating between theCRT and RCT, based on a patient's changing needs and conditions. Thedrug therapy controller produces a drug delivery signal to direct a drugrelease from drug delivery device 630. In one embodiment, drug deliverydevice 630 releases the drug while the drug delivery signal is present.In another embodiment, drug delivery device 630 starts releasing thedrug upon receiving a drug delivery signal and stops releasing the drugupon receiving another drug delivery signal. In another embodiment, drugdelivery device 630 releases the drug for a predetermined time periodupon receiving the drug delivery signal. In a specific embodiment, thepredetermined time period is specified by the drug delivery signal.

In one embodiment, the electrical and drug therapies are closed-loopcontrolled by using one or more sensors sensing the need and the effectof the electrical and drug therapies. Sensor processing circuit 625processes the signal sensed by sensor circuit 621 for therapy controller626 to determine whether to start, stop, or adjust the electrical and/ordrug therapies. In one embodiment, sensor processing circuit 625produces the therapeutic control signals as one or more parameters basedon the one or more signals sensed by sensor circuit 621. In oneembodiment, sensor processing circuit 625 includes an event detector todetect one or more predetermined events indicative of a need to start,stop, or adjust the electrical and/or drug therapies. The one or moreparameters produced by sensor processing circuit 625 include parametersindicative of the detection of the event and/or measured parametersassociated with the detected event. In one specific embodiment, theevent includes an abnormal condition. In one embodiment, sensor circuit621 includes a plurality of sensors to sense multiple signals used bytherapy controller 626 to determine whether to start, stop, or adjustthe electrical and/or drug therapies. Each of the multiple signals maybe used by therapy controller 626 to control the drug therapy, theelectrical therapy, or coordinated electrical and drug therapies. Theone or more signals sensed by sensor circuit 621 include, but are notlimited to, one or more of an electrogram indicative of arrhythmiaand/or heart rate variability, a physiological signal indicative ofischemia, a metabolic signal indicative of a cardiac metabolic level(rate of metabolism of cardiac cells), a thoracic impedance, anintracardiac or intravascular pressure, a cardiac output or strokevolume, a neural signal indicative of activities of the autonomicnervous system, a signal indicative of renal function, a signalindicative of heart sounds, a signal indicative of respiratory sounds, asignal indicative of a strain of myocardial tissue, and a temperaturesignal. Examples of such signals and their use in controlling electricaland drug therapies are discussed in U.S. patent application Ser. No.10/742,574, U.S. patent application Ser. No. 10/788,906, and U.S. patentapplication Ser. No. 10/862,716, all assigned to Cardiac Pacemakers,Inc., which are hereby incorporated by reference in their entirety.Other methods and sensors for directly or indirectly detecting an eventor condition demanding the start, stop, or adjustment of the electricaland/or therapies are also usable by system 100.

Drug delivery device 630 includes a drug pump 631, a drug reservoir 632,a reservoir filling port 633, and a drug level monitoring circuit 634.Drug pump 631 draws the drug from drug reservoir 632 and pumps the druginto the lumen of a drug delivery lead (such as one of the drug deliveryleads discussed above) to deliver the drug by releasing it from one ormore drug delivery ports in lead system 108. Drug reservoir 632 containsthe drug. Reservoir filling port 633 is connected to drug reservoir 632to allow filling of the drug reservoir. In one embodiment, reservoirfilling port 633 is constructed on an implantable housing of theimplantable medical device 210, such as illustrated as reservoir filingport 214 in FIGS. 2-5. Drug level monitoring circuit 634 monitors thelevel of the drug in drug reservoir 632. In one embodiment, when thelevel of the drug in drug reservoir 632 falls below a predeterminedminimum level, drug level monitoring circuit 634 produces a drug levelalert signal to be transmitted to the external system through telemetrylink 140. If deemed necessary, the physician or other caregiver refillsdrug reservoir 632 by injecting the drug through reservoir filling port633 using a syringe and a hollow needle.

Depending on the therapeutic functions and intended use of implantablemedical device 210, lead system 108 includes one or more of drugdelivery lead, pacing lead, defibrillation lead, pacing/defibrillationlead, drug delivery pacing lead, drug delivery defibrillation lead, anddrug delivery pacing/defibrillation lead. In one embodiment, lead system108 includes at least one drug delivery lead for intracardiac deliveryof the drug. In another embodiment, lead system 108 includes at leastone drug delivery lead for epicardial delivery of the drug. In anotherembodiment, lead system 108 includes at least one drug delivery lead forintravascular delivery of the drug. In one embodiment, lead system 108further include one or more sensors of sensor circuit 621 incorporatedinto one or more leads. In one specific embodiment, sensor circuit 621includes a pressure sensor housed within implantable medical device 210.Lead system 108 includes at least one lead having two or more lumens.One of the lumens is configured to allow intracardiac pressure sensing.

In one embodiment, implantable medical device 210 is capable ofdelivering a plurality of drugs, with the delivery of each drugindividually controllable. In this embodiment, drug reservoir 632includes a plurality of drug compartments each containing one drug. Drugpump 631 includes a plurality of pumps each draws drug from onecompartment of drug reservoir 632 to deliver the drug in response to adrug delivery signal produced by therapy controller 626. The drugdelivery signal is specific to each drug to be delivered. In oneembodiment, the drugs are delivered to the same location, with thetiming of delivery individually controllable for each drug. In anotherembodiment, lead system 108 includes a plurality of drug delivery leadsfor delivering different drugs to different locations.

External device 150 includes an external user input 652, an externaldisplay 654, an external device controller 656, an external telemetrymodule 644, and an external network interface 662. In one embodiment,external user input 652 receives the external command controlling theelectrical and/or drug therapies from the physician or other caregiver.In a further embodiment, external user input 652 also receives othercommands or instructions to control the operation implantable medicaldevice 210. In one embodiment, the external command controlling theelectrical and drug therapies is sent from remote device 170. Externaldevice 150 relays the external command to implantable medical device210. In one specific embodiment, the external command includes a drugdelivery command. External device 150 transmits the drug deliverycommand to implantable medical device 210 to result in a production ofthe drug delivery signal by the drug delivery controller of therapycontroller 626. External telemetry module 644 provides for a telemetryinterface allowing external device 150 to communicate with implantablemedical device 210 via telemetry link 140. External network interface662 provides for a network interface allowing external device 150 tocommunicate with remote device 170 via network 160.

Telemetry link 140 is a wireless bidirectional data transmission linksupported by implant telemetry module 642 and external telemetry module644. In one embodiment, telemetry link 140 is an inductive couple formedwhen two coils—one connected to implant telemetry module 642 and theother connected to external telemetry module 644—are placed near eachother. In another embodiment, telemetry link 140 is a far-fieldradio-frequency telemetry link allowing implantable medical device 210and external device 150 to communicate over a telemetry range that is atleast ten feet.

Remote device 170 includes a remote signal processor 674, a remote userinterface 676, a remote device controller 678, and a remote networkinterface 664. By executing one or more predetermined algorithms, remotesignal processor 674 processes signals transmitted from implantablemedical device 210 and external device 150. In one embodiment, remotesignal processor 674 analyzes signals acquired by implantable medicaldevice 210 and transmitted to remote device 170, such as the one or moresignals sensed by sensor circuit 621, to determine the need forstarting, stopping, or adjusting the electrical and/or drug therapies.Remote user interface 676 includes a remote user input to allow thephysician or other caregiver to enter the external command from a remotelocation. In one embodiment, remote user interface 676 receives the druglevel alert signal generated by drug level monitoring circuit 634 andinforms the physician or other caregiver that the drug level in drugreservoir is low. Remote device controller 678 controls the overalloperation of remote device 170. In one embodiment, remote devicecontroller 678 generates commands controlling implantable medical device210 and/or external device 150 based on the received signals and theexternal command. In one embodiment, remote device controller 678executes an automatic algorithm to control the electrical and/or drugtherapies, such as when the physician or other caregiver is notimmediately available. Remote network interface 664 provides for aninterface allowing communication between remote device 170 and externaldevice 150 via network 160.

Network 160 provides long distance bi-directional communication betweenexternal device 150 and remote device 170. It allows management ofmultiple implantable systems, each implanted in a different patient,from a central facility. In one embodiment, this allows prompt responseby a physician or other caregiver at the central facility as demanded bythe condition of a patient. In one embodiment, network 160 is based on awireless communications system. In another embodiment, network 160 isbased on a wired communications system. In one embodiment, network 160utilizes portions of a standard communications system such as theInternet, a telephone system, or a radio frequency telemetry system.

FIG. 7 is a block diagram illustrating one embodiment of the circuit ofportions of a CRM system 700. CRM system 700 is an embodiment of CRMsystem 100 and includes an implantable system and an external system.The implantable system includes implantable medical device 410 and leadsystem 108. Implantable medical device 410 includes implantable pulsegenerator 410A and implantable drug delivery device 410B, which arefastened to each other. The external system includes external device150, network 160, and remote device 170.

Implantable pulse generator 410A includes a sensor circuit 721A, pulseoutput circuit 622, a pulse delivery controller 724A, and an implanttelemetry module 742A. Implant telemetry module 742A provides for atelemetry interface allowing implantable pulse generator 410A tocommunicate with external device 150 via a telemetry link 740A.

Sensor circuit 721A senses one or more signals each indicative of a needto deliver the electrical therapy. In one embodiment, sensor circuit721A further senses one or more signals each indicative of a need todeliver the drug therapy. These signals are transmitted to the externalsystem via telemetry link 140 for controlling the drug therapy throughthe external system. In one embodiment, sensor circuit 721A includes anelectrogram sensing amplifier circuit to sense one or more electrograms.In a further embodiment, sensor circuit 721A includes one or moreimplantable sensors to sense additional physiological signals. In oneembodiment, the one or more implantable sensors include at least onesensor housed in can 411A of implantable pulse generator 410A. Inanother embodiment, the one or more implantable sensors include at leastone sensor incorporated into a lead of lead system 108.

Pulse delivery controller 724A controls the operation of implantablepulse generator 410A. Pulse delivery controller 724A includes a sensorprocessing circuit 725A, a therapy controller 726A, and a commandreceiver 727A. Sensor processing circuit 725A processes the one or moresignals sensed by sensor circuit 721A to produce diagnostic and/ortherapeutic control signals, as discussed above for sensor processingcircuit 625 and sensor circuit 621. Command receiver 727A receives theexternal command entered by the physician or other caregiver and sentfrom the external system through implant telemetry module 742A andtelemetry link 140. Therapy controller 726A controls the delivery of theelectrical therapy based on the therapeutic control signals and theexternal command.

Therapy controller 726A includes an electrical therapy controller. Theelectrical therapy controller includes a pacing algorithm executioncircuit to control the delivery of pacing pulses by executing a pacingalgorithm. In one embodiment, the pacing algorithm execution circuitexecutes a pacing algorithm designed to enhance one or more effects ofthe drug therapy. In a specific embodiment, the pacing algorithmexecution circuit includes one or more of a CRT pacing algorithmexecution circuit and an RCT pacing algorithm execution circuit. In afurther specific embodiment, the pacing algorithm execution moduleexecutes a dynamic pacing algorithm that dynamically adjusts pacingparameters, such as alternating between the CRT and RCT, based on apatient's changing needs and conditions.

In one embodiment, the electrical therapy is closed-loop controlled byusing one or more sensors sensing the need and the effect of theelectrical and drug therapies. Sensor processing circuit 725A processesthe signal sensed by sensor circuit 721A for therapy controller 726B todetermine whether to start, stop, or adjust the electrical and/or drugtherapies. In a further embodiment, sensor circuit 721A and sensorprocessing circuit 725A also senses and processes one or more signals toprovide closed-loop control of the drug therapy by using one or moresensors sensing the need and the effect of the electrical and drugtherapies. The signals or parameters derived from the signals aretransmitted to implantable drug delivery device 410B through theexternal system for implantable drug delivery device 410B to determinewhether to start, stop, or adjust the drug therapy. In one embodiment,sensor circuit 721A includes sensor circuit 621 or portions of it, andsensor processing circuit 725A includes sensor processing circuit 625 orportions of it.

Implantable drug delivery device 410B includes a sensor circuit 721B, adrug delivery controller 724B, drug pump 631, drug reservoir 632,reservoir filling port 633, drug level monitoring circuit 634, and animplant telemetry module 742B. Implant telemetry module 742B providesfor a telemetry interface allowing implantable drug delivery device 410Bto communicate with external device 150 via a telemetry link 740B.

Sensor circuit 721B senses one or more signals each indicative of a needto deliver the drug therapy. In one embodiment, sensor circuit 721Bincludes an electrogram sensing amplifier circuit to sense one or moreelectrograms. In a further embodiment, sensor circuit 721B includes oneor more implantable sensors to sense additional physiological signals.In one embodiment, the one or more implantable sensors include at leastone sensor housed in can 411B of implantable drug delivery device 410B.In another embodiment, the one or more implantable sensors include atleast one sensor incorporated into a lead of lead system 108.

Drug delivery controller 724B controls the operation of implantable drugdelivery device 410B. Drug delivery controller 724B includes a sensorprocessing circuit 725B, a therapy controller 726B, and a commandreceiver 727B. Sensor processing circuit 725B processes the one or moresignals sensed by sensor circuit 721B to produce diagnostic and/ortherapeutic control signals. Command receiver 727B receives an externalcommand sent from the external system through implant telemetry module742A and telemetry link 140. Therapy controller 726B controls thedelivery of the drug therapy based on the therapeutic control signalsand the external command.

Therapy controller 726B includes a drug therapy controller. The drugtherapy controller produces a drug delivery signal to direct a drugrelease from drug pump 631. In one embodiment, drug pump 631 releasesthe drug while the drug delivery signal is present. In anotherembodiment, drug pump 631 starts releasing the drug upon receiving adrug delivery signal and stops releasing the drug upon receiving anotherdrug delivery signal. In another embodiment, drug pump 631 releases thedrug for a predetermined time period upon receiving the drug deliverysignal. In a specific embodiment, the predetermined time period isspecified by the drug delivery signal.

In one embodiment, the drug therapy is closed-loop controlled by usingone or more sensors sensing the need and the effect of the electricaland drug therapies. Sensor processing circuit 725B processes the signalsensed by sensor circuit 721B for therapy controller 626 to determinewhether to start, stop, or adjust the drug therapy. In one embodiment,sensor circuit 721B includes sensor circuit 621 or portions of it, andsensor processing circuit 725B includes sensor processing circuit 625 orportions of it. In one embodiment, the drug therapy is closed-loopcontrolled by using one or more sensors of sensor circuit 721A inimplantable pulse generator 410A. Signals sensed by sensor 721A andprocessed by sensor processing circuit 725A are transmitted toimplantable drug delivery device 410B for use by drug deliverycontroller 724B to determine to start, stop, or adjust the drug therapy.

Telemetry link 740A is a wireless bidirectional data transmission linksupported by implant telemetry module 742A and external telemetry module644. Telemetry link 740B is another wireless bidirectional datatransmission link supported by implant telemetry module 742B andexternal telemetry module 644. In one embodiment, telemetry links 740Aand 740B are time-sharing telemetry links that allow one ofcommunication between implantable pulse generator 410A and externaldevice 150 and communication between implantable drug delivery device410B and external device 150 at one instant. In another embodiment,telemetry links 740A and 740B allows simultaneous or concurrentcommunications between implantable pulse generator 410A and externaldevice 150 and between implantable drug delivery device 410B andexternal device 150.

FIG. 8 is a flow chart illustrating one embodiment of a method formaking a CRM system that delivers combined electrical and drugtherapies. In one embodiment, the method is applied to make implantablesystem 215 or 315.

A pulse generator circuit is provided at 800. The pulse generatorcircuit includes a pulse output circuit to deliver electrical pulses tothe heart through one or more leads with electrodes. Depending on theintended use of the implantable system, the pulse generator circuitincludes one or more of a pacemaker circuit, a circuit for delivering aCRT, a circuit for delivering an RCT, and a cardioverter/defibrillatorcircuit.

A drug delivery device including a drug reservoir is provided at 810.The drug reservoir is filled with a drug to be delivered to thecardiovascular system. In one embodiment, a control circuit is providedto control the pulse generator circuit and the drug delivery device todeliver combined electrical and drug therapies. In one specificembodiment, the electrical and drug therapies are temporallycoordinated. In one further embodiment, a sensor circuit is provided tosense one or more signals each indicative of a cardiac function. Afeedback control circuit is provided to control the delivery of theelectrical pulses and the drug therapies based on at least the sensedone or more signals.

The pulse generator circuit and the drug delivery device areencapsulated using an implantable housing at 820 to form an implantablemedical device. In one embodiment, the implantable housing includes ahermetically sealed can to house the pulse generator circuit, the drugdelivery device, the control circuit including the feedback controlcircuit, and the sensor circuit.

A self-resealable reservoir filling port is constructed on theimplantable housing at 830. The self-resealable reservoir filling portincludes a self-resealable diaphragm that allows filling of the drugthrough a hollow needle. To fill or refill the drug reservoir, the drugis drawn into a syringe with the hollow needle. The hollow needle isinserted through the self-resealable diaphragm. When the filling iscompleted, the diaphragm reseals itself as the hollow needle is pulledout.

In addition to the implantable medical device, at least one drugdelivery lead is provided. The lead is to be connected to theimplantable medical device. In one embodiment, an implantable lead withone or more electrodes is provided to allow delivery of the electricalpulses. A lumen is provided within the implantable lead for passing thedrug from the drug delivery device to one or more drug delivery portsincorporated into the implantable lead. In another embodiment, animplantable pacing lead with one or more electrodes is provided to allowdelivery of the electrical pulses, and a separate implantable drugdelivery lead is provided to allow delivery of the drug. The drugdelivery lead includes a lumen for passing the drug from the drugdelivery device to one or more drug delivery ports incorporated into theimplantable drug delivery lead.

FIG. 9 is a flow chart illustrating one embodiment of another method formaking a CRM system delivering combined electrical and drug therapies.In one embodiment, the method is applied to make implantable system 415or 515.

An implantable pulse generator is provided at 900. The implantable pulsegenerator includes an implantable pulse generator housing such as ahermetically sealed can. Examples of the implantable pulse generatorinclude, but are not limited to, an implantable pacemaker, animplantable CRT device, an implantable RCT device, and an implantablecardioverter/defibrillator.

An implantable drug delivery device is provided at 910. The implantabledrug delivery device includes a drug reservoir, a self-resealablereservoir filling port, and an implantable drug delivery device housingsuch as a hermetically sealed can. The self-resealable reservoir fillingport is constructed on the implantable drug delivery device housing toallow filling of the drug reservoir through a hollow needle.

The implantable pulse generator housing and the implantable drugdelivery device housing are fastened to each other at 920 to form animplantable medical device. In one embodiment, implantable housinghaving approximately identical major contours are provided for use asthe implantable pulse generator housing and the implantable drugdelivery device housing. In one embodiment, the implantable drugdelivery device housing is glued to the implantable pulse generatorhousing using a biocompatible adhesive. In another embodiment, theimplantable drug delivery device housing is welded to the implantablepulse generator housing. In another embodiment, the implantable drugdelivery device housing is braced to the implantable pulse generatorhousing. In general, the implantable drug delivery device housing isconfigured for attachment to the implantable pulse generator housing.The implantable drug delivery device can be fastened to the implantablepulse generator using any method for permanently attaching theimplantable drug delivery device housing to the implantable pulsegenerator housing.

In addition to the implantable medical device, one or more pacing leads,defibrillation leads, pacing/defibrillation leads, drug delivery leads,drug delivery pacing leads, drug delivery defibrillation leads, and/ordrug delivery pacing/defibrillation leads are provided. Depending on theintended use of the implantable system, one or more of such leads areselected to be connected to the implantable pulse generator and theimplantable drug delivery device.

It is to be understood that the above detailed description is intendedto be illustrative, and not restrictive. Although the present therapy isdescribed in the context of cardiac therapy as a specific example, it isunderstood that many other applications are possible. Combinedelectrical and drug therapies can be used to treat conditions other thancardiac disorders. Other embodiments, including any possible permutationof the system components discussed in this document, will be apparent tothose of skill in the art upon reading and understanding the abovedescription. The scope of the invention should, therefore, be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

1. A cardiac rhythm management (CRM) system, comprising: an implantablemedical device including: a pulse output circuit to deliver electricalpulses; a drug delivery device including: a drug reservoir to contain adrug; and a reservoir filling port connected to the drug reservoir; animplant controller, coupled to the pulse output circuit and the drugdelivery device, to control delivery of the electrical pulses and thedrug; and an implantable housing to contain the pulse output circuit,the drug delivery device, and the implant controller, wherein thereservoir filling port is constructed on the implantable housing andincludes a self-resealable portion adapted to allow filling of the drugreservoir using a hollow needle.
 2. The system of claim 1, wherein thepulse output circuit comprises a pacing circuit to deliver pacingpulses.
 3. The system of claim 1, wherein the pulse output circuitcomprises a cardioversion/defibrillation circuit to delivercardioversion/defibrillation shocks.
 4. The system of claim 1, whereinthe drug delivery device further comprises a drug level monitoringcircuit, coupled to the drug reservoir, to monitor a level of the drugin the drug reservoir.
 5. The system of claim 4, wherein the drugdelivery device further comprises a drug pump to deliver the drug fromthe drug reservoir, and further comprising at least one implantable leadincluding: a proximal end and a distal end, the proximal end connectedto the drug delivery device; one or more drug delivery ports; and alumen extending within the implantable lead from the proximal end to theone or more drug delivery ports to allow passage of the drug from thedrug delivery device to the one or more drug delivery ports.
 6. Thesystem of claim 5, wherein the one or more drug delivery ports comprisesat least one drug delivery port at or near the distal end of the atleast one implantable lead.
 7. The system of claim 5, wherein the one ormore drug delivery ports comprises a plurality of drug delivery portsdistributed along the at least one implantable lead.
 8. The system ofclaim 5, wherein the lumen is configured to accommodate a portion of aguidewire for implanting the at least one implantable lead.
 9. Thesystem of claim 5, wherein the distal end of the implantable lead isconfigured for endocardial placement.
 10. The system of claim 5, whereinthe distal end of the implantable lead is configured for epicardialplacement.
 11. The system of claim 5, wherein the at least oneimplantable lead further comprises one or more electrodes to which theelectrical pulses are delivered from the pulse output circuit.
 12. Thesystem of claim 5, further comprising at least a further implantablelead including one or more electrodes to which the electrical pulses aredelivered from the pulse output circuit.
 13. The system of claim 1,wherein the implantable medical device further comprises a sensorcircuit, coupled to the implant controller, to sense one or more signalsindicative of a need to deliver at least one or more of the electricalpulses and the drug, and wherein the implant controller comprises asensor processing circuit coupled to the sensor circuit and a therapycontroller coupled to the sensor processing circuit, the therapycontroller adapted to control the delivery of the electrical pulses andthe drug based on at least the one or more signals.
 14. The system ofclaim 13, wherein the therapy controller comprises a pacing algorithmexecution circuit including one or more of a cardiac resynchronizationtherapy (CRT) algorithm execution circuit and a remodeling controltherapy (RCT) algorithm execution circuit.
 15. The system of claim 13,wherein the implant controller comprises a command receiver to receivean external command, and the therapy controller is adapted to controlthe delivery of the electrical pulses and the drug based on at least theone or more signals and the external command.
 16. The system of claim15, further comprising an external system communicating with theimplantable medical device, the external system including a userinterface including a user input device to receive the external command.17. A cardiac rhythm management (CRM) system, comprising: an implantablepulse generator to deliver electrical pulses, the implantable pulsegenerator including: a pulse generator circuit; and a first implantablehousing configured to encapsulate the pulse generator circuit; and animplantable drug delivery device to deliver a drug, the implantable drugdelivery device including: a drug reservoir to contain the drug; asecond implantable housing configured to encapsulate portions of astructure of the implantable drug delivery device including the drugreservoir, the second implantable housing fastened to the firstimplantable housing; and a reservoir filling port constructed on thesecond implantable housing, the reservoir filling port including aself-resealable portion adapted to allow filling of the drug reservoirthrough a hollow needle.
 18. The system of claim 17, wherein theimplantable pulse generator comprises one of a pacemaker, a cardiacresynchronization therapy (CRT) device, a remodeling control therapy(RCT) device, a cardioverter/defibrillator, and apacemaker-cardioverter/defibrillator.
 19. The system of claim 17,wherein the implantable drug delivery device further comprises: a druglevel monitoring circuit, coupled to the drug reservoir, to monitor alevel of the drug in the drug reservoir; and a drug pump to delivery thedrug from the drug reservoir.
 20. The system of claim 19, wherein theimplantable drug delivery device further comprises: a sensor circuit tosense one or more signals indicative of a need to deliver the drug; anda drug delivery controller to control the delivery of the drug, the drugdelivery controller including a sensor processing circuit coupled to thesensor circuit and a therapy controller coupled to the sensor processingcircuit, the therapy controller adapted to control the delivery of thedrug based on at least the one or more signals.
 21. The system of claim20, wherein the drug delivery controller further comprises a commandreceiver to receive an external command controlling the delivery of thedrug.
 22. The system of claim 21, further comprising an external systemcommunicating with the implantable medical device, the external systemincluding a user interface including a user input device to receive theexternal command.
 23. The system of claim 17, wherein the secondimplantable housing is glued to the first implantable housing using abiocompatible adhesive.
 24. The system of claim 17, wherein the secondimplantable housing is welded to the first implantable housing.
 25. Thesystem of claim 17, wherein the second implantable housing is braced tothe first implantable housing.
 26. The system of claim 17, wherein thesecond implantable housing is soldered to the first implantable housing.27. The system of claim 17, wherein the first implantable housing andthe second implantable housing have approximately identical majorcontours.
 28. A medical device assembly, comprising: an implantable drugdelivery device including: a drug reservoir to contain the drug; animplantable housing adapted to contain portions of a structure of theimplantable drug delivery device including the drug reservoir, theimplantable housing configured to be attached to an implantable cardiacrhythm management (CRM) device; and a reservoir filling port constructedon the implantable housing, the reservoir filling port including aself-resealable portion adapted to allow filling of the drug reservoirusing a hollow needle; and means for fastening the implantable drugdelivering device to the implantable CRM device.
 29. The medical deviceassembly of claim 28, wherein the implantable drug delivery devicefurther comprises: a drug level monitoring circuit, coupled to the drugreservoir, to monitor a level of the drug in the drug reservoir; and adrug pump to delivery the drug from the reservoir.
 30. The medicaldevice assembly of claim 29, further comprising at least one implantablelead including: a proximal end and a distal end, the proximal endconfigured to be connected to the drug delivery device; one or more drugdelivery ports; and a lumen extending within the implantable lead fromthe proximal end to the one or more drug delivery ports to allow passageof the drug from the drug delivery device to the one or more drugdelivery ports.
 31. The medical device assembly of claim 28, wherein themeans for fastening the implantable drug delivering device to theimplantable CRM device comprises a biocompatible adhesive.
 32. A methodfor making an implantable cardiac rhythm management (CRM) system,comprising: providing a pulse generator circuit adapted to deliverelectrical pulses to one or more electrodes; providing a drug deliverydevice including a drug reservoir; encapsulating the pulse generatorcircuit and the drug delivery device using an implantable housing; andincorporating a self-resealable reservoir filling port onto theimplantable housing to allow filling of the drug reservoir using ahollow needle.
 33. The method of claim 32, wherein providing the pulsegenerator circuit comprises providing one or more of a pacemakercircuit, a circuit delivering a cardiac resynchronization therapy (CRT),a circuit delivering a remodeling control therapy (RCT), and acardioverter/defibrillator circuit.
 34. The method of claim 33, furthercomprising providing a control circuit to control the pulse generatorand the drug delivery device.
 35. The method of claim 34, furthercomprising providing a sensor circuit to sense one or more signals eachindicative of a cardiac function.
 36. The method of claim 35, whereinproviding a control circuit comprises providing a feedback controlcircuit to control a drug delivery based on the one or more signals. 37.The method of claim 32, further comprising providing at least oneimplantable lead including the one or more electrodes to which theelectrical pulses are delivered.
 38. The method of claim 37, whereinproviding the at least one implantable lead comprises providing a lumenfor passing the drug from the drug delivery device to one or more drugdelivery ports incorporated into the at least one implantable lead. 39.The method of claim 38, further comprising providing at least onefurther implantable lead including a lumen for passing the drug from thedrug delivery device to one or more drug delivery ports incorporatedinto the at least one further implantable lead.
 40. A method for makingan implantable medical device, comprising: providing an implantablepulse generator including an implantable pulse generator housing;providing an implantable drug delivery device including a drugreservoir, an implantable drug delivery device housing, and aself-resealable reservoir filling port constructed on the implantabledrug delivery device housing to allow filling of the drug reservoirusing a hollow needle; and fastening the implantable drug deliverydevice housing to the implantable pulse generator housing.
 41. Themethod of claim 40, wherein providing the implantable pulse generatorcomprises providing one of an implantable pacemaker, an implantablecardiac resynchronization therapy (CRT) device, a implantable remodelingcontrol therapy (RCT) device, an implantable cardioverter/defibrillator,and an implantable pacemaker-cardioverter/defibrillator.
 42. The methodof claim 41, further comprising providing implantable device housingshaving approximately identical major contours for use as the implantablepulse generator housing and the implantable drug delivery devicehousing.
 43. The method of claim 41, wherein fastening the implantabledrug delivery device housing to the implantable pulse generator housingcomprises gluing the implantable drug delivery device housing to theimplantable pulse generator housing using a biocompatible adhesive. 44.The method of claim 41, wherein fastening the implantable drug deliverydevice housing to the implantable pulse generator housing compriseswelding the implantable drug delivery device housing to the implantablepulse generator housing.
 45. The method of claim 41, wherein fasteningthe implantable drug delivery device housing to the implantable pulsegenerator housing comprises bracing the implantable drug delivery devicehousing to the implantable pulse generator housing.
 46. The method ofclaim 41, wherein fastening the implantable drug delivery device housingto the implantable pulse generator housing comprises soldering theimplantable drug delivery device housing to the implantable pulsegenerator housing.